The present invention relates to a closure clip according to the preamble of independent claims.
In particular, the present invention relates to a closure clip for closing tubular or bag-shaped packing casing for packing loosely goods or foodstuff, like fruit or vegetables. The closure clip comprises two arms extending at least substantially in a plane and at least substantially parallel to each other, having first and second ends and inner and outer surfaces facing from the arms and a bottom portion arranged in the plane defined by the two arms, having an inner and an outer surface and connecting the two arms by their first ends, thereby forming a substantially U-shaped closure clip.
The present invention further relates to a die closing a closure clip. The die has an approximately cuboid die body including a first, horizontal top surface, a second, vertical front surface and a third, vertical side surface, and an approximately semicircular recess extending from the center of the horizontal top surface into the die body. The die further comprises two guide channels for guiding the second ends of the closure clip, the guide channels are arranged in the surface of the semicircular recess parallel to each.
For storing and/or transporting loosely goods or foodstuff, like fruit or vegetables, said goods may be packed in a tubular or bag-shaped packing casing. Said tubular or bag-shaped casing may be made of e.g. web-like material. While packing, a predetermined portion or number of said goods is filled into the bag-shaped casing or a tubular casing portion closed at one end.
Clipping machines are used for packing said goods into respective packing casings, in particular, for applying closure means, like substantially U-shaped closure clips, to said packing casing for closing the packing casing. Additionally, loops for pendulous storing said packed goods, wrist straps and/or labels may be attached to the packing casing by means of the closure clip.
A generally known clipping machine for closing said packing casing and for attaching a loop or the like to the packing casing comprises, amongst others, displacer elements for gathering the filled tubular or bag-shaped packing casing and for providing a plait-like portion, and a punch and die assembly for attaching the closure clip to the plait-like portion and for closing said clip around said plait-like portion. After a plait-like portion is formed by the displacer elements, a clip is conveyed to the plait-like portion, positioned around the plait-like portion and closed by bending the arms of the U-shaped closure clip around the plait-like portion. For deforming the closure clip, said clip is pressed by the punch pushing the clip toward the die, with the tips of its arms against the die. The die comprises guide channels for guiding the arms of the clip along each other while being bent around the plait-like portion.
From EP patent application 0 809 592, a substantially U-shaped closure clip for closing bags or film tubes is known, having a bottom portion and two arms coupled to said bottom portion. At the free ends of each of the two arms, latch elements are arranged for fixedly connecting the free ends of the arms, when the closure clip is in the closed configuration, thereby the closure clip forms a closed ring. At the inner surface of the bottom portion and the arms, teeth project inwards the closure clip. In the closed configuration, said teeth engaging the bag or film tube material to prevent the closure clip from slipping off the bag or film tube material. The closure clips may be coupled to each other for forming a chain which may be stored on a clip supply, like a reel. The device for closing said closure clip comprises a die and punch assembly. The die is formed by a solid body including a recess. Said recess has tapering side surfaces for guiding the free ends of the closure clip towards each other and for coupling the free ends of the arms by the latch elements. The punch for pushing the closure clip toward the die has a lower surface directed towards the bottom portion of the closure clip. Said lower surface matches the outer surface of the bottom portion of the closure clip.
Loosely goods or foodstuff are often packed in bags of web material made of plastic. For closing said bags, clips of the above known kind are used. In case of plastic bags closed by plastic closure clips, said clips may slip off the bag neck, since the frictional force applied to the bag material by the clip may be not sufficient. If said closure clips comprise teeth, said teeth may engage the bag material, But in case of heavy goods or additionally forces to the clip, e.g. by carrying the bag, said teeth may be bent and the closure clip may be slip off the bag neck. By using metal clips, said clips may damage the bag material.